While I will not argue that intelligence is a critically important aspect of labor, I also think that there's another key aspect of it, that is completely different in quantity and application - attention.  There are a lot of service jobs that just need someone to really pay attention - no, more than that, to pay attention and to care what happens.  This isn't innovation, this isn't solving new problems - this is just doing things that need to be done, and doing them correctly so that everybody is better off.

Medicine?  Most of it is just paying attention to the sick, and trying to help them.  Sure, medical researchers are out there trying to solve new problems, but most nurses and doctors working with the public are just applying their attention and care.

Education is a field where, arguably, research has made the field worse, not better.  Academic education programs seems to be a black hole of mediocre intellects pondering problems that are only problems for themselves, and then forcing their half-baked solutions on the actual teachers in the field - most of whom need, more than anything, the time and energy to really pay attention to their students.

Law and government - sure, directing national policy is a realm for the intellect, but helping people get their drivers license, ensuring fair and respectable legal representation, and police work are about paying attention, being there, and caring how things go.

Cooking, crafting, massage, hair/nail/beauty care, repair and renovation, and a hundred more that aren't coming to mind - all of these are key services that dramatically improve the quality of life for people around them, and thus contribute greatly to human wealth, and all of them are based largely on attention and care.